Abstract: A control system for an automatic transmission, in which a first frictional engagement element and a second frictional engagement element are released according to a shift from a running range to a non-running range. The shift from the running range to the non-running range is detected, and the reduction in the oil pressure of the second frictional engagement element is controlled on the basis of the reduction in the oil pressure of the first frictional engagement element when the shift from the running range to the non-running range is detected.

Abstract: An automatic transmission control system is equipped with a pressure modulating valve for regulating the engaging pressure to be supplied to frictional engagement elements for setting respective gear stages of the automatic transmission, a signal pressure output valve for providing signal pressure, and a switching valve.

Abstract: A transfer portion connected to the output shaft of a transmission portion has a front planetary gear unit the output element of which is connected to the front wheels and a rear planetary gear unit the output element of which is connected to the rear wheels, the two units being connected to each other by a common element. The output shaft of the transmission portion is directly connected to the input element of either of the planetary gear units, while the same is connected to the input element of the other planetary gear unit via a clutch C.sub.3. Furthermore, the input element of the other planetary gear unit is connected to the case via a brake B.sub.4. Therefore, the reduction function can be realized in cooperation with the two planetary gear units. As a result, the four-wheel drive device is lightened.

Abstract: A continuously variable speed transmission having a belt drive continuously variable speed transmission in which a belt is wrapped around primary and secondary pulleys each supported on a shaft and each consisting of a pair of sheaves capable of relatively moving axially, and a forward/reverse rotation changeover mechanism. The belt drive continuously variable speed transmission is provided with a pressure adjusting cam mechanism for applying an axial force corresponding to a transmitted torque to at least one of the pulleys, ball screw mechanisms for axially moving the movable sheaves of the pulleys. A fluid torque converter is disposed on the transmission upstream side of the primary pulley. In the belt drive continuously variable speed transmission, the pressure adjusting cam mechanism produces and axial force corresponding to the transmitted torque to clamp the belt, and the power is transmitted by the effect of this clamping force without belt slip.

Abstract: A transmission provided in a power transmitting system and having at least a transmission mechanism and a forward/reverse rotation changeover mechanism controlled on the basis of signals from a control section. The transmission includes a plurality of mechanical actuators (e.g., ball screw mechanisms) capable of converting torques into thrust forces to operate the transmission operation mechanisms by the thrust forces, a motor (e.g., an electric motor) serving as a common torque generation source for the mechanical actuators, a divergence mechanism for distributing and transmitting a torque from the motor to the mechanical actuators, and a changeover mechanism for transmitting the torque distributed from the divergence mechanism to at least one of the mechanical actuators.

Abstract: In an overdrive planetary gear unit of an automatic transmission, a helical planetary pinion has its front portion cut to form an cutout portion and to have an axial-direction cross section asymmetrical in the direction of its rotation axis in order to uniformize, in the axial direction, the load imposed upon a bearing disposed around the circumference of the pinion shaft.In a front planetary gear unit of a main transmission of the automatic transmission, a helical planetary pinion has its rear portion cut to form an cutout portion and to have an axial-direction cross section asymmetrical in the direction of its rotation axis in order to uniformize the load imposed upon a bearing disposed around the circumference of the pinion shaft.It is thereby possible to reduce the weight of each planetary pinion and, hence, the centrifugal force acting on the pinion.

Abstract: An automatic transmission hydraulic controller having a multiplicity of hydraulic servos for respectively controlling a multiplicity of frictional engagement elements. A hydraulic pressure to be supplied to the hydraulic servos is applied to accumulator chambers of a multiplicity of accumulators. A line pressure to be supplied to the hydraulic servos is produced by a primary regulator valve and an engine output pressure control valve is controlled by an electrical signal from a control section to produce a hydraulic pressure corresponding to the engine output. Each of at least two particular ones of the multiplicity of accumulators has a back pressure chamber formed at the rear of a piston. The pressure receiving area of this back pressure chamber and that of the corresponding accumulator chamber are substantially equal to each other.

Abstract: In an electronic controller for an automatic transmission having at least one driving circuit incorporating a switching device for driving a solenoid used as an actuator, at least one monitor circuit for detecting an abnormal state of the actuator, and a control section connected to these circuits, an emergency power cutoff circuit is provided between the solenoid driving circuit and the positive terminal of a battery (solenoid driving power source). The switching operation of the emergency power cutoff circuit is freely controlled to effect fail-safe control on the basis of a signal which is output from a microcomputer if, for example, the switching device in the controller malfunctions by short-circuiting.

Abstract: A hydraulic controller for an automatic transmission, having a band brake having a large stopping force based on a self-boosting effect against rotation in a self-binding direction and having a comparatively small stopping force against rotation in the unbinding direction, a modulator valve for producing a modulator pressure by reducing a line pressure, a band brake hydraulic servo having a brake engaging hydraulic chamber and a brake releasing hydraulic chamber. A line pressure is supplied to the band brake hydraulic servo to stop rotation in the self binding direction when a predetermined transmission speed is selected. The line pressure is also supplied the band brake hydraulic servo to stop rotation in the unbinding direction when another transmission speed is selected. A modulator pressure is supplied to the brake engaging hydraulic chamber to stop the rotation in the self-binding direction of the band brake and to allow the rotation in the unbinding direction when an intermediate speed is selected.

Abstract: In a system for controlling a vehicle by exchanging signals between an electronic controller for controlling a vehicle transmission and another electronic controller for controlling a vehicle engine, the transmission controller incorporates a monitor circuit which receives, via an interface circuit of the engine controller, a signal output from the transmission controller through a communication circuit, and which is capable of detecting abnormalities of the interface circuit of the engine controller. If an abnormality of the interface circuit of the engine controller takes place such that the engine torque cannot be reduced although the transmission controller issues an instruction to reduce the engine torque, the transmission controller maintains the line pressure instead of reducing the same to cope with such a situation, thus effecting fail-safe control.

Abstract: A pressure control valve has a valve sleeve, a spool valve mounted for sliding in the valve sleeve in response to a load by an electromagnet, a spring load, and an output pressure feedback load, and the electromagnet portion capable of moving the spool valve. The spool valve has an oil passage capable of feeding back the output pressure, the feedback oil passage being formed diagonally in the land portion. A periphery of an end surface of the land portion, or the same of the supply port, output port, or the exhaust port of the sleeve is provided with a cutout. Output pressure generated at the output port is transmitted through the feedback oil passage, thereby damping and stabilizing the operation of the spool valve. Since the cutout is formed as described above, a rapid pressure change due to the movement of the spool valve can be eliminated, preventing generation of buzz.

Abstract: A fail-safe control device for an electronically controlled automatic transmission mounted on a vehicle is provided with a sensor for sensing the number of revolutions input to the transmission and a sensor for sensing the number of revolutions output from the transmission or from a car speed sensor. The actual gear ratio of the transmission is calculated in accordance with the number of revolutions input to the transmission and the number of revolutions output from the transmission or from the car speed sensor each obtained from said sensors. The time taken for changing the actual gear ratio at the time of shift initiation to the fixed gear ratio after the shift is measured. A predetermined shift time which has been stored is compared with the thus-measured time for the purpose of detecting a failure of the transmission.

Abstract: A multi-disk brake for an automatic transmission having a plurality of annular outer lamellae having a larger diameter and a plurality of annular inner lamellae having a smaller diameter, the outer and inner lamellae being alternately arranged and interleaved in the axial direction. The outer lamellae are splined to the transmission case while the inner lamellae are rotatably supported on the case. The multi-disk brake has an engagement/disengagement mechanism capable of pressing the outer and inner lamellae so as to bring the same into frictional engagement and capable of disengaging and releasing the outer and inner lamellae from each other. A support member is inserted into the lowermost portion of an annular gap formed between outer the peripheral surfaces of the outer lamellae and the inner peripheral surface of the case, the support member supporting the outer lamellae biases them upward, thereby preventing any rotational drag motion of the outer lamellae.

Abstract: A pressure control valve includes a spool valve slidable in a valve sleeve having a supply port, an output port and an exhaust port, and adapted to receive a load caused by an electromagnet and applies through a push rod, a spring load, and an output pressure feedback load. The balance among the loads is arranged to control the output pressure at a level corresponding to the electric signal input to the electromagnet. Provision is made for preselecting the gradient of the attractive force of the electromagnet with respect to the stroke of a plunger slidable within the core of the electromagnet and for adjusting the axial position of the plunger. Specifically, the electromagnet includes a coil assembly, a cylindrical core having an axially extending opening through which receives the push rod, and a cup-shaped plunger fixed to one end of the push rod and covering the core. The inner cylindrical surface of the cup-shaped plunger is tapered to converge toward the bottom of the plunger.

Abstract: A lamp output protective circuit for an electronic controller having a first npn transistor connected to an output terminal through which a lamp is supplied with electric power, a resistor connected between the emitter of said first npn transistor and the ground, and a second npn transistor having its collector connected to the base of the first npn transistor, its emitter to the ground and its base to a point between the emitter of the first npn transistor and the resistor. The base of the first npn transistor and the collector of the second npn transistor are connected to a signal line of the electronic controller connected to a power source.

Abstract: A continuously variable belt transmission of the type comprising: primary and secondary pulleys, each of which comprises a pair of axially opposed sheaves supported on a shaft, one of the sheaves being movable and the other being fixed; a belt wound around these pulleys; a pressure adjusting mechanism for imparting to at least one of these pulleys an axial force which corresponds to torque transmitted; and mechanical actuators for axially shifting the movable sheaves of these pulleys, wherein: first thrust bearings are respectively interposed between the backsides of the movable sheaves and one ends of the mechanical actuators; a first automatic aligning mechanism is provided for supporting at least one of the races of each the first thrust bearing; and axial forces occurring at the pulleys are carried by the shafts directly, or via the first thrust bearings, the first automatic aligning mechanisms and the mechanical actuators, or via the pressure adjusting mechanism.

Abstract: A pressure control valve including an electromagnet portion, a pressure governing valve portion coupled to the electromagnet portion and hydraulic oil enclosed in said electromagnet portion. The pressure governing valve portion includes a valve sleeve and a spool valve slidably mounted in the valve sleeve so that an output pressure corresponding to an input signal to the electromagnet portion is provided. The electromagnet portion includes a push rod which slides in tandem with the spool valve, a core surrounding the push rod, a coil assembly disposed on the outer surface of the core, and a plunger secured to the push rod so that the spool valve slides responsive to the input signal. An oil passage is provided between the core and the coil assembly as that movable portions of the electromagnet portion move without any resistance from the hydraulic oil.

Abstract: In a fail-safe control device for an electronically controlled automatic transmission to be mounted on a vehicle, a sensor for the number of revolution input to a T/M is newly provided for the electronically controlled automatic transmission, and an actual gear ratio of the T/M is calculated in accordance with the number of revolution input to the T/M and the number of revolution output from the T/M or the car speed. If the calculated actual gear ratio is coincided with the formal gear ratio, it is determined that the state is normal, while if they are not coincided with each other, it is determined that the T/M is in a failure state. As a result of this, failure detection of the T/M is performed. Therefore, in a case when the T/M is in a failure state, a driver can take a measure, for exmple, by performing an emergency control. Furthermore, the occurrence of the failure can be displayed by a detected failure displaying device so that the driver can take a measure such as a repair.

Abstract: A fail-safe control device for an electronically controlled automatic transmission to be mounted on a vehicle arranged in such a manner that the number of engine revolution or the number of revolution input to a T/M is detected, the duration of the engine revolving state is counted, and it is determined that a failure of the engine water temperature sensor occurs if the engine water temperature detected by the engine water temperature sensor after a predetermined time elapse counted is lower than a predetermined temperature. As a result of this, a proper fail-safe control against the failure of the engine water temperature sensor can be performed.

Abstract: A fail-safe control device for an electronically controlled automatic transmission to be mounted on a vehicle, the fail-safe control device: detects the battery voltage; previously stores a standard battery voltage; makes a comparison between the thus-detected battery voltage and the above-described standard battery voltage; and switches to an emergency mode of turning off all of shift solenoids when the voltage deviates from the standard upon the comparison. As a result of this, generation of defects that shifting from high speed gear stage to a lower speed gear stage due to defective operation of the shift solenoid and disconnection or the like due to the overvoltage of the solenoid can be prevented. Furthermore, if a failure is detected, it can be notified to a drive.